As we’ve learned, foods high in saturated and trans fats play a major role in driving insulin resistance—the ‘gum in the lock’ that blocks insulin’s action.

However, even higher-fat plant foods, such as avocados and nuts, can slow the reversal of insulin resistance—particularly in prediabetes or long-standing type 2 diabetes—by maintaining excess fat within muscle and liver cells.

A simple way to translate this science into daily food choices is by using the Traffic Light Guide. This approach guides people towards a low-fat plant-based diet, with around 10–15% of calories from fat. This means, for men, a maximum of 30 grams of fat per day, and for women, closer to 22–25 grams of fat per day. These levels have been shown in randomised controlled trials to improve insulin resistance markers and diabetes outcomes.

Simply by swapping to a whole food plant-based diet, you can cut your diabetes risk by 20–30%. However, if your goal is to reverse insulin resistance, lowering fat intake is key.

The traffic light system

🟢 Green Light foods (eat in abundance)

Fill at least half your plate with low-fat whole plant foods, including:

• Fruits
• Starchy vegetables (potato, sweet potato, pumpkin)
• Non-starchy vegetables (broccoli, spinach, carrots)
• Intact whole grains (oats, brown rice, quinoa)
• Legumes (beans, lentils, chickpeas)

These foods are naturally low in fat (generally < 5% of energy), high in fibre, and rich in nutrients. They support insulin sensitivity by helping clear stored fat from cells while promoting stable blood glucose control.

🟡 Yellow Light foods (use sparingly)

These are whole plant foods that contain moderate amounts of fat, such as:

• Avocado and durian
• Olives
• Coconut
• Nuts and nut butters
• Seeds
• Tofu and tempeh

While nutritious, their fat content can add up quickly. For example, ¼ avocado contains around 7 grams of fat. In the early stages of improving insulin resistance, large amounts may slow progress if total fat intake exceeds therapeutic targets.

🔴 Red Light foods (minimise or avoid)

These foods are highest in saturated and trans fats, and are associated with worsening insulin resistance:

• Animal products
• Added oils
• Fried foods
• Highly processed foods

Reducing or eliminating these foods supports improvements in both metabolic and cardiovascular health.

Transition tips

Some individuals track food intake using apps such as Cronometer and MyFitnessPal, or seek support from clinicians experienced in plant-based nutrition.

Please note: Food or calorie tracking is not recommended for individuals with a current or past history of disordered eating.

Increasing carbohydrates from Green Light plant foods is both safe and beneficial long term. These foods support pancreatic function and improve insulin sensitivity when dietary fat is reduced.

However, if fat intake remains high, blood glucose levels may rise temporarily due to ongoing fat accumulation within cells, impairing insulin action.

During the transition to a low-fat, plant-based diet, some people may also see short-term rises in blood glucose (often over 1–4 weeks) as stored fat begins clearing from muscle cells. This is a recognised physiological adjustment and typically improves with dietary consistency.

Because medication needs can change quickly, it’s essential to work with a healthcare professional to monitor glucose levels and adjust medications safely—particularly for those using insulin or sulfonylurea medications.

Recap

With support from your healthcare team:

• Increase Green Light foods
• Be mindful of Yellow Light portions
• Reduce or eliminate Red Light foods

Many people see significant improvements using this framework alone. If progress plateaus, further reducing total dietary fat intake may be helpful.

For more of a deep dive, we recommend the NY Times best-selling book Mastering Diabetes and its corresponding US-based coaching program.